Interface IP-Address OK? Method Status ProtocolįastEthernet0/0 10.10.14. so that you could use a loopback as the source, regardless of the interface which the packets actually use. You can configure static routes, OSPF, EIGRP, etc between routers and advertise the. When the ping packet leaves router (call it R1) through the fa0/0 interface, the source IP of that packet it set to the IP of fa0/0, right. command the router will time out in the 3 minutes as you have mentioned because it has not way to route to the Loopback you specified in the BGP message. and if you want that the telnet source address be controlled only for this telnet then you should use the command line option of: telnet 10.1.1.1 /source-interface loopback 0. With the ping above, that means the source address is 192.168.1.254. If you want that the telenet source address will always be the specified address then you should use the configuration option of: ip telnet source-interface. Ip nat inside source list 7 pool ovrld overloadĪccess-list 7 permit 10.10.12.0 0.0.0.255 In a typical Cisco router its possible to ping a host from the routers OS. When R1 sends a ping, it will use its IP address on the closest interface to the destination. R1 ping 2.2.2.2 Type escape sequence to abort. Let’s ping the loopback IP address from both R1 and R2. Ip nat pool ovrld 192.168.1.250 192.168.1.250 prefix-length 24 TACACS+ or RADIUS can use the loopback address as a source address for AAA functions and thereby reducing the administration overhead of having to add every IP address of the router to the AAA server. Ip address dhcp client-id FastEthernet0/0 Serial0/0/0 unassigned YES NVRAM down downīRI0/2/0 unassigned YES NVRAM administratively down downīRI0/2/0:1 unassigned YES unset administratively down downīRI0/2/0:2 unassigned YES unset administratively down downĪsync0/3/0 unassigned YES NVRAM down down Interface IP-Address OK? Method Status Prot ocolįastEthernet0/0 192.168.1.121 YES DHCP up upįastEthernet0/1 10.10.12.254 YES NVRAM up up Can anyone help please? I have two routers. I am able to ping the tunnel ip address on the router that it's configured on. So it is better to avoid to advertise in BGP the loopback used as source address for iBGP sessions.Friends, I created a GRE tunnel and I can't ping the tunnel destination from either router. Unless the Cisco router has proxy-arp enabled, which most do by default. Also, make sure the PC has the default gateway set to the Fa0/0 interfaces IP address or the PC wont be able to hit the x.x.255.1 loopback0 address on the router. It would be used if the IGP route disappears but if this happen you would see the loopback address in BGP with next-hop the same IP address and this would not be acceptable by other routers. The PC should now be able to ping the 1841s loopback IP, 192.168.255.1. For example I have the following network: The configuration on each router is: ROUTER 1. This should not work however as they are more than 2 hops away. On the other way if 10.1.1.1/32 is published in IGP there is no real reason to publish it also in iBGP as that route will never be used for its higher admin distance. If I pair up two routers using eBGP using loopbacks as the source and one router between them, the. If it is not able to find an indipendent way to resolve the next-hop 10.1.1.1 it is a dead lock. The reason is that in iBGP the next-hop is not changed but preserved so a remote router iBGP speaker would see something like However for ping/traceroute, like IOS, no such command exists and it defaults to use the sourceIP of the the interface towards. For many host services the source-interface command can be used to set this. If we speak of iBGP deployment with an IGP like OSPF or IS-IS used to advertise loopbacks you want to keep separate the IGP infrastructure subnets used for building up the network including the iBGP sessions from service or customer oriented prefixes that are usually published in BGP only.Īdvertising a loopback interface in iBGP is not forbidden but it does not solve the issues of making that loopback "reachable" by other devices. Ive an issue where the source of my pings from a router are ideally sourced from a loopback.
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